Fast growth of the pervasive computing and handheld/communication industry has generated exploding demand for high capacity non-volatile solid-state data storage devices. Current technology like flash memory, that utilizes a floating gate from which electrons tunnel, has several drawbacks such as slow access speed, limited endurance, and the integration difficulty. Flash memory (NAND or NOR) also faces significant scaling problems.
Resistive sense memories are promising candidates for future non-volatile and universal memory by storing data bits as either a high or low resistance state. One such memory, MRAM, features non-volatility, fast writing/reading speed, almost unlimited programming endurance and zero standby power. The basic component of MRAM is a magnetic tunneling junction (MTJ). MRAM switches the MTJ resistance by using a current induced magnetic field to switch the magnetization of the MTJ. As the MTJ size shrinks, the switching magnetic field amplitude increases and the switching variation becomes more severe. Resistive RAM (RRAM) is another resistive sense memory that has a variable resistance layer that can switch between a high resistance state and a low resistance state (for example by the presence or absence of a conductive filament) by application of a current or voltage.
However, many yield-limiting factors must be overcome before resistive sense memory enters the production stage. Improvements in resistive sense memory are always welcome.